WO2023017656A1

WO2023017656A1 - Metal-resin composite body

Info

Publication number: WO2023017656A1
Application number: PCT/JP2022/016256
Authority: WO
Inventors: 慎青柳; 基貴若松; 良聡小林; 康則佐々木
Original assignee: Ｊｘ金属株式会社
Priority date: 2021-08-11
Filing date: 2022-03-30
Publication date: 2023-02-16
Also published as: JP2023025926A; TW202306753A; TWI808728B; JP7182675B1

Abstract

A metal-resin composite body 1 is provided with a metal plate 2, and a resin member 3 affixed to the metal plate 2, and has an internal space which is partitioned by means of a sealing member that includes the resin member 3, wherein: the resin member 3 has a frame-like shape extending on the metal plate 2 so as to enclose the perimeter of the internal space; there are weld lines 7 in one or two locations in the circumferential direction of the frame-shaped resin member 3; and, on a resin-covered surface in which the metal plate 2 is covered by the resin member 3, there is a rough undulating surface formed by means of rectangular recessed portions 5a and rectangular protruding portions 5b that are aligned alternately in each of one direction and a direction perpendicular thereto, in a plan view of the resin-covered surface.

Description

metal-resin composite

This specification discloses a technique related to a metal-resin composite comprising a metal plate and a resin member fixed to the metal plate.

For metal-resin composites manufactured by insert molding, etc., it is required to improve the adhesion between the metal plate and the resin member.

In this regard, for example, in Patent Document 1, "A first punch having a first predetermined curvature and having a plurality of grid-like first protrusions is used to form a first punch on a flat metal plate. a step of performing a second press with the first punch in a direction intersecting with the first press; and a step of performing a fourth press with the second punch in a direction intersecting the third press, wherein the The third pressing and the fourth pressing are performed on a portion where the first pressing and the second pressing are not performed, a method for manufacturing a metal member having unevenness on the surface” and “the first and second recesses arranged in a different position from the first recesses and having a different shape from the first recesses are arranged in a grid pattern. .

JP 2017-208486 A

By the way, in some metal-resin composites, an internal space is partitioned by a sealing member including the resin member, for example, by providing another resin member on the resin member fixed to the metal plate. For example, in a metal-resin composite used for a semiconductor device using a metal plate as a lead frame, a semiconductor chip is enclosed in the internal space.

If airtightness of the internal space is not sufficiently secured by a resin member, etc., moisture-containing air may permeate the internal space from the outside, causing problems such as malfunction due to contact with the moisture of the heat-generating semiconductor chip. can occur. In particular, metal-resin composites used in semiconductor devices are exposed to repeated temperature changes due to changes in the external environment as well as turning on and off the semiconductor chip enclosed in the internal space. The technique described in Patent Literature 1 has room for improvement from the viewpoint of further improving the hermeticity of the internal space.

This specification discloses a metal-resin composite that can improve the sealing of the internal space by the resin member.

One metal-resin composite disclosed in this specification includes a metal plate and a resin member fixed to the metal plate, and an internal space is partitioned by a sealing member containing the resin member, The resin member has a frame shape extending on the metal plate so as to surround the inner space, and weld lines are present at one or two places in the circumferential direction of the frame-shaped resin member, and the metal plate A resin-coated surface covered with a resin member has a roughened uneven surface formed by rectangular concave portions and rectangular convex portions that are alternately arranged in one direction and in each of the orthogonal directions in a plan view of the resin-coated surface. is.

Another metal-resin composite disclosed in this specification includes a metal plate and a resin member fixed to the metal plate, and an internal space is partitioned by a sealing member including the resin member, The resin member has a frame shape extending on the metal plate so as to surround the inner space, and weld lines are present at one or two places in the circumferential direction of the frame-shaped resin member, and the metal plate A roughened plating layer is included on the resin-coated surface covered with the resin member.

According to the metal-resin composite described above, it is possible to improve the sealing of the internal space by the resin member.

1 is a plan view showing a metal-resin composite of one embodiment; FIG. FIG. 2 is a plan view showing a metal plate included in the metal-resin composite of FIG. 1; 2 is a plan view showing the metal-resin composite of FIG. 1 with a semiconductor chip mounted thereon; FIG. 3 is a partially enlarged plan view of the metal plate of FIG. 2; FIG. 3 is a perspective view showing a part of the uneven surface of the metal plate of FIG. 2; FIG. FIG. 3 is a plan view of an uneven surface of the metal plate of FIG. 2 and a modification thereof; FIG. 4 is a plan view showing an example of forming an uneven surface on a resin-coated surface of a metal plate; FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6(a); FIG. 10 is a plan view showing a metal plate included in a metal-resin composite of another embodiment; FIG. 2 is a bottom view of the metal-resin composite of FIG. 1; FIG. 10 is a plan view showing a metal-resin composite of still another embodiment; FIG. 2 is a cross-sectional view and a plan view showing a specimen produced using a metal-resin composite in an example.

Embodiments of the metal-resin composite described above will be described in detail below.
A metal-resin composite 1 illustrated in FIG. 1 includes a metal plate 2 having an out-of-plane contour shape such as a rectangular shape, and a resin member 3 fixed to the metal plate 2 .

As shown in FIGS. 1 and 2, the illustrated metal plate 2 has a substantially rectangular through hole 4 penetrating in the plate thickness direction in the center. In the metal-resin composite 1, a frame-shaped resin member 3 having, for example, rectangular inner and outer contour shapes in a plan view is provided around the through hole 4 of the metal plate 2, and inside thereof, for example, A semiconductor chip 51 as shown in FIG. 3 is arranged. In this case, the metal plate 2 functions as a lead frame that supports the semiconductor chip 51 and connects with external wiring, and the metal-resin composite 1 is used for a semiconductor device. Metal plate 2 is made of, for example, copper, aluminum, iron, or an alloy thereof.

The space inside the frame-shaped resin member 3 is surrounded by the resin member 3 and a sealing member such as another resin member (not shown) to define an internal space in which the semiconductor chip 51 is arranged and enclosed. In this metal-resin composite 1, an internal space partly formed by a through-hole 4 is defined by a sealing member containing a resin member 3, and the resin member 3 extends so as to surround the internal space. is provided in

The through hole 4 provided in the metal plate 2 is not limited to a rectangular shape as shown in the drawing, but may have a square shape, other polygonal shape, or a circular shape depending on conditions such as the shape and configuration of the semiconductor chip 51 arranged therein. etc. can be used. Also, the out-of-plane contour shape of the metal plate 2 may be changed to a shape other than the rectangular shape shown in the drawing. The inner and outer contours of the frame-shaped resin member 3 in plan view can also be appropriately changed to a shape other than a rectangular shape.

Here, it may be required that the internal space that is subsequently partitioned by the metal-resin composite 1 be sufficiently sealed. For example, when the semiconductor chip 51 is enclosed in the internal space, if the internal space is not sufficiently sealed, moisture-containing air may permeate into the internal space from the outside, causing the semiconductor chip 51 to malfunction. .

In order to improve the airtightness of the internal space, in this embodiment, the resin-coated surface of the metal plate 2 covered with the resin member 3 is provided with an uneven surface 5 as illustrated in the enlarged view of FIG. As shown in the perspective view of FIG. 5, the uneven surfaces 5 are arranged alternately in one direction and in the orthogonal direction, which is the direction orthogonal to the one direction, in plan view of the resin-coated surface. It is formed by a rectangular concave portion 5a and a rectangular convex portion 5b. The uneven surface 5 presents a so-called checkered pattern in plan view.

When the resin member 3 is provided on the resin-coated surface of the metal plate 2 having the uneven surface 5 provided on the resin-coated surface by integral molding or the like, the uneven surface 5 allows air to pass from the outside to the internal space. is blocked. This effectively suppresses permeation of moisture between the resin member 3 and the resin-coated surface, and as a result, it is possible to greatly improve the hermeticity of the internal space.

Regarding the direction in which the uneven surface 5 is arranged, in this example, the “one direction” is the direction along the long side of the rectangular metal plate 2 (horizontal direction in FIGS. 2 and 4), and the “perpendicular direction” is the metal plate 2 (in FIGS. 2 and 4, the vertical direction). However, the "one direction" and the "perpendicular direction" are directions that are inclined with respect to the long side or the short side, respectively, and the rectangular concave portions 5a and the rectangular convex portions 5b are arranged side by side obliquely with respect to the long side or the short side. , the uneven surface 5 can also be formed.

The planar shape of the rectangular concave portion 5a and the rectangular convex portion 5b that form the uneven surface 5 may be rectangular as shown in the drawing, or may be square. In plan view, the dimensions and shapes of the rectangular recesses 5a and the rectangular projections 5b can be different from each other. The shapes and dimensions may be different from each other. As shown in FIG. 5, the concave-convex surface 5 is formed by a rectangular concave portion 5a and a rectangular convex portion 5b, which have substantially the same shape and dimensions in plan view.

When the rectangular concave portions 5a and rectangular convex portions 5b of the concave-convex surface 5 are provided side by side in each of the one direction and the orthogonal direction, if the rectangular concave portions 5a and the rectangular convex portions 5b are shifted even slightly in the direction orthogonal to the direction in which they are arranged, they are alternately arranged in each direction. can be regarded as lined up. In other words, if the forming positions of the mutually adjacent rectangular recesses 5a and the mutually adjacent rectangular protrusions 5b do not match each other in one direction and the orthogonal direction, the rectangular recesses 5a and the rectangular protrusions 5b are not aligned. It is assumed that they are arranged alternately in each direction. For example, in the uneven surface 5 of FIG. 6A, the rectangular concave portions 5a and the rectangular convex portions 5b are arranged in one direction (horizontal direction in FIG. 6) and in an orthogonal direction (vertical direction in FIG. 6). They are arranged alternately without overlapping each other in the orthogonal direction. On the other hand, in the uneven surface 15 of FIG. 6(b), the rectangular concave portions 15a and the rectangular convex portions 15b are arranged alternately, partially overlapping each other in a direction perpendicular to the one direction, when viewed in the same direction. It is However, from the viewpoint of improving the airtightness of the internal space, as shown in FIG. are arranged alternately without overlapping each other in a direction orthogonal to the arranging direction. This is because the relatively flat rectangular protrusions 5b do not continue in the path of air entering the internal space from the outside.

When the planar shape of the rectangular concave portion 5a and the rectangular convex portion 5b is rectangular, the long side length La of each of the rectangular concave portion 5a and the rectangular convex portion 5b is 0.17 mm to 0.25 mm, and the short side length Lb is 0.17 mm to 0.25 mm. is preferably 0.04 mm to 0.10 mm. If the length of the long side or short side is too long, the number of unevenness will decrease, and the sealing of the internal space may decrease. There is concern that the amount of resin that enters 5a will decrease, the strength of the resin will decrease, and the hermeticity will deteriorate.
Further, it is preferable that the pitch Pa in the long side direction of the rectangular concave portions 5a is 0.38 mm to 0.46 mm, and the pitch Pb in the short side direction is 0.11 mm to 0.17 mm. If the pitches Pa and Pb are too large, the rectangular protrusions 5b sandwiched between the adjacent rectangular recesses 5a will not have enough bulges, leaving a large number of flat surfaces, possibly degrading the airtightness. On the other hand, if the pitches Pa and Pb are too small, the adjacent rectangular recessed portion 5a is crushed and deformed, and the strength of the resin there may be reduced, resulting in poor sealing performance. The pitches Pa and Pb mean the distances between the central points of the rectangular concave portions 5a adjacent to each other across the rectangular convex portion 5b in one direction or in the orthogonal direction.

The concave-convex surface 5 formed by the rectangular concave portions 5a and the rectangular convex portions 5b can be formed on the resin-coated surface by, for example, pressing the resin-coated surface. In this press working, although illustration is omitted, a punch having a plurality of protrusions having shapes corresponding to the rectangular recesses 5a arranged side by side on the tip surface can be used.

When forming the uneven surface 5 with a relatively small pitch Pa and/or Pb, it is preferable to perform a plurality of pressing steps including a first pressing step and a second pressing step. Specifically, first, as shown in FIG. 7(a), a first pressing step is performed by pressing a punch having a plurality of protrusions on the tip surface against the resin-coated surface. Thereby, the first concave portion group R1 is formed on the resin-coated surface. Next, as shown in FIG. 7(b), a punch having a plurality of protrusions on the tip surface is pressed against positions shifted in a predetermined direction such as one direction and an orthogonal direction on the resin-coated surface to obtain a second punch. Two pressing steps are performed. The punch used in the second pressing step may be the same as the punch in the first pressing step, but may have a different shape. In the second pressing step, the second recess group R2 overlaps the first recess group R1 at least partially on the resin-coated surface, and the second recess group R2 is formed between the rectangular recesses 5a of the first recess group R1. is formed. The rectangular convex portion 5b is provided between adjacent rectangular concave portions 5a. As a result, the rectangular concave portions 5a and the rectangular convex portions 5b can be densely formed on the resin-coated surface.

When the uneven surface 5 is provided, the top surface 5c of the portion of the rectangular convex portion 5b that protrudes most toward the resin member 3 (the outer side of the metal plate 2 in the plate thickness direction) may be a flat surface. As shown in the cross-sectional view along the plate thickness direction in FIG. As a result, the shear strength in the plane direction of the resin is improved, and the deterioration of the sealing property due to exposure to repeated temperature changes is alleviated. In addition, since the flat rectangular projections 5b do not continue along the path for air to enter the internal space from the outside, the airtightness of the internal space can be improved. Such a rectangular projection 5b having a convex curved surface on the resin member 3 side can be obtained by forming the uneven surface 5 using a punch having a plurality of projections on the tip surface as described above. In some cases, the thickness between the rectangular recesses 5a rises outward (upper side in FIG. 8) in the plate thickness direction due to the formation of the depressions corresponding to the recesses 5a.
Here, the depth (recess depth) of the rectangular recess 5a is preferably 0.20 mm or less, more preferably 0.10 mm or less. If the depth of the concave portion is too large, the extension in the plate thickness direction becomes large, and there is a possibility that the deformation will be so great as to affect the subsequent process (molding). The recess depth refers to the distance from the deepest position of the bottom surface of the rectangular recess 5a to the highest position of the top surface 5c of the rectangular protrusion 5b adjacent to the rectangular recess 5a in the plate thickness direction. When the rectangular recess 5a is provided, the depth of the recess is preferably 0.02 mm to 0.20 mm, more preferably 0.04 mm to 0.10 mm.

In order to improve the hermeticity of the internal space, it is desirable that the uneven surface 5 provided on the resin-coated surface is roughened by etching, plating, or the like to increase the surface roughness Ra. As a result, the uneven surface 5 becomes a roughened uneven surface, and the anchor effect of the resin on the roughened uneven surface and the rectangular concave portions 5a and the rectangular convex portions 5b formed thereon combine to reduce the internal space. Airtightness is greatly improved.

Specifically, the surface roughness Ra of the roughened uneven surface is preferably 0.2 μm or more. This surface roughness Ra means arithmetic mean roughness based on JIS B0601:2001. The surface roughness Ra of the roughened uneven surface is the arithmetic mean roughness measured at the position of the top surface 5c of the rectangular convex portion 5b forming the roughened uneven surface. The roughened surface of the roughened uneven surface can be confirmed with a stereomicroscope, SEM, or laser microscope. If the roughening conditions are the same, the surface roughness of the roughened uneven surface and the surface roughness of the roughened surface without the uneven surface 5 are equivalent. When the surface is not roughened, the surface becomes glossy, and when the surface is roughened, the surface becomes non-glossy.

Instead of or in addition to providing the uneven surface 5 described above, a roughening plated layer 6 can be provided on the resin-coated surface as in the embodiment shown in FIG. By providing the roughened plating layer 6 on the resin-coated surface, the resin member 3 is sufficiently adhered to the resin-coated surface through the roughened plating layer 6. Not necessarily. However, when the uneven surface 5 is provided on the resin-coated surface and the roughened plating layer 6 is further provided thereon to form a roughened uneven surface, it is possible to further improve the hermeticity of the internal space. The presence or absence of the roughened plating layer 6 can be confirmed with an optical microscope.

The plating thickness of the roughened plating layer 6 provided on the resin-coated surface is preferably 2.0 μm to 6.0 μm, more preferably 3.0 μm to 5.0 μm. If the plating thickness of the roughening plating layer 6 is too thin, there is concern that the adhesion of the resin member 3 to the resin-coated surface will be insufficient. On the other hand, if the plating thickness of the roughening plating layer 6 is too thick, the cost may increase.

The roughened plated layer 6 can be made of copper, silver, or the like, but is preferably nickel plated and may contain nickel. In the case of the roughening plated layer 6 containing nickel, there is an advantage that the roughening shape and the degree of roughening can be easily controlled. Moreover, the roughening plated layer 6 may contain at least one selected from the group consisting of nickel, copper and silver.

In order to form the roughened plating layer 6 on the resin-coated surface of the metal plate 2, for example, although not shown, roughening is performed while the surface of the metal plate 2 on which the roughened plating layer 6 is not formed is covered with a mask. It can be carried out by electroplating the metal plate 2 in a plating solution containing the plating metal of the plating layer 6 . In another embodiment, the rough plating layer 6 may be formed on the entire surface of the metal plate 2 without using a mask.

In addition, although there may be a part where the uneven surface 5 and / or the roughened plating layer 6 does not exist in a part of the resin coated surface, the uneven surface 5 and / or the roughened plating layer 6 is covered over the entire resin coated surface. It is preferable to provide it from the viewpoint of ensuring sufficient adhesion between the resin member 3 and the metal plate 2 .

Since the frame-shaped resin member 3 is provided on the metal plate 2 provided with the roughened plating layer 6 or the roughened uneven surface as described above, insert molding can be performed.

In insert molding, the metal plate 2 is placed in an injection mold having a cavity corresponding to the shape of the resin member 3, and the resin material is injected into the cavity from the gate of the injection mold. The resin material that has flowed into the cavity from the gate flows through the cavity having a shape corresponding to the frame-shaped resin member 3, joins along the way, and fills the cavity. After that, the resin material is cooled and solidified in the cavity. Thereby, a metal-resin composite 1 in which the resin member 3 is fixed to the metal plate 2 is obtained.

Here, in the resin member 3 after molding, a weld line 7 is formed at a position where the resin material flowing through the cavity during injection joins. In the illustrated embodiment, as an example, two gates are provided at respective positions of the cavity corresponding to the central positions of the two long sides of the frame-shaped resin member 3 whose inner and outer contours are both rectangular in plan view. As a result of this, the resin material flows bifurcated into the cavity from each gate and merges, and as a result, two weld lines 7 are formed at the central positions of the two short sides of the resin member 3. . Alternatively, when there is only one gate, the weld line 7 can be formed at one position in the circumferential direction of the frame-shaped resin member 3 at the position furthest from the gate. The weld line 7 may be formed in a linear shape such as a straight line or a curved line that crosses the frame-shaped resin member 3 in the width direction, and can be confirmed by observing the outer surface of the resin member 3 with the naked eye or an optical microscope. be.

The weld line 7 is preferably one or two in the circumferential direction of the frame-shaped resin member 3 . This is because, in addition to providing the roughened uneven surface or the roughened plating layer 6 on the metal plate 2, by setting the number of weld lines 7 to two or less, the hermeticity of the internal space is greatly improved. In other words, if there are three or more weld lines 7, the airtightness of the internal space is reduced, increasing the possibility that moisture-containing air can easily permeate the internal space.

Although the material of the resin member 3 is not particularly limited, for example, liquid crystal polymer, acrylonitrile-butadiene-styrene copolymer synthetic resin (ABS), polyamide (PA), polypropylene (PP), polyester thermoplastic elastomer (TPC), ), polyacetal (POM), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and the like can be used.

By the way, the illustrated metal plate 2 is provided with cutouts 8a to 8c at a plurality of locations extending toward the outside of the through hole 4. As shown in FIG. More specifically, in this example, the resin member 3 is connected to the through hole 4 and directed outward through the position where the resin member 3 is arranged on each of the outer sides of the rectangular metal plate 2 in the longitudinal direction (horizontal direction in FIG. 1). A rectangular notch 8a extending and widening, a polygonal notch 8b having a larger area than the rectangular notch 8a, and the outer side of the metal plate 2 in the width direction (vertical direction in FIG. 1) at the center position in the longitudinal direction of the metal plate 2. are connected to the through-hole 4 and extend outward to form a notch 8c that widens into a slightly elongated rectangular shape. Each notch 8a to 8c is formed through the metal plate 2 in the plate thickness direction.

The resin member 3 connects the cutouts 8a to 8c and the through holes 4 not only on the surface Sf side of the metal plate 2 but also on both sides of the back surface Sb side of the metal plate 2 as shown in FIG. It is provided in the shape of a frame around the through-hole 4 through a space that is a part. As a result, in a part of the frame-shaped resin member 3 in the circumferential direction, the metal plate 2 is sandwiched from both sides by the resin member 3 , but in the remaining part having the above-mentioned space, the metal plate 2 is inside the resin member 3 . Metal plate 2 does not exist.

In this way, when the frame-shaped resin member 3 is provided by sandwiching the metal plate 2 from both sides in the plate thickness direction at a part in the circumferential direction, the weld line 7 described above is formed by the frame-shaped resin member 3 is preferably formed at a location where the metal plate 2 does not exist inside the resin member 3 in the circumferential direction of . The presence of the weld line 7 at the place where the metal plate 2 does not exist inside the resin member 3 and the resin member 3 is not supported by the metal plate 2 can further improve the hermeticity of the internal space. If the weld line 7 exists inside the resin member 3 where the metal plate 2 exists, moisture-containing air enters the interior from the interface between the metal plate 2 and the portion of the resin member 3 where the weld line 7 is formed. It can permeate the space.

The metal plate 2 has an inner edge portion 2a on the surface Sf side that protrudes further toward the through hole 4 than the resin member 3, and is connected to the semiconductor chip 51 by bonding wires 52 at the inner edge portion 2a.

FIG. 11 shows a metal-resin composite 1 of another embodiment. In the metal-resin composite 1 of FIG. 11 , except that a protruding portion 9 that protrudes outward from the resin member 3 is provided at a location where the weld line 7 is formed in the circumferential direction of the frame-shaped resin member 3 . , and has substantially the same configuration as that shown in FIG. The protrusion 9 protrudes from the resin member 3 in a direction substantially parallel to the surface of the metal plate 2 . Although not shown, the protruding portion 9 may be provided so as to protrude inside the resin member 3 (toward the through hole), or may be provided so as to protrude from the resin member 3 in the plate thickness direction.

When the resin member 3 is molded using an injection mold having a cavity in which the protrusion 9 is provided in the resin member 3, the resin material injected into the cavity merges at the location where the protrusion 9 is formed. The flow is changed to the side and the layers of the weld are slightly destroyed. As a result, the strength of the resin member 3 is improved, and the sealing performance of the internal space is accordingly improved.

The protrusion 9 may then be cut and removed. In this case, a cut mark is formed and exists in the place where the weld line 7 of the resin member 3 is formed. The cut marks can be visually confirmed. If there is a cut mark at the location where the weld line 7 of the resin member 3 is formed, it is presumed that the protruding portion 9 was previously formed there, thereby reinforcing the weak portion caused by the weld line 7. can do.

Next, we made a prototype of the metal-resin composite as described above and confirmed its effect, which will be described below. However, the description herein is for illustrative purposes only and is not intended to be limiting.

(Uneven surface)
A metal-resin composite as shown in FIG. 1 was produced.
In Examples 1 to 4 and Comparative Examples 3 and 4, as described with reference to FIG. A pressing step and a second pressing step were performed to form rectangular concave portions and rectangular convex portions that were alternately arranged in one direction and each direction perpendicular thereto, thereby providing an uneven surface (rectangular uneven surface). The long side length La of each rectangular recess was 0.21 mm, the short side length Lb was 0.07 mm, the pitch Pa in the long side direction was 0.42 mm, and the pitch Pb in the short side direction was 0.14 mm. The dimensions of the rectangular concave portion and the rectangular convex portion in plan view were substantially the same. Table 1 shows the depth of the rectangular recess (recess depth).

In Comparative Example 2, the resin-coated surface of the metal plate was provided with an uneven surface (linear uneven surface) in which a plurality of linear recesses extending in one direction were formed at intervals in a direction orthogonal to the straight line direction. The width of the linear recesses was 0.04 mm, and the pitch of the linear recesses was 0.1 mm. Linear protrusions were formed between adjacent linear recesses.

In Examples 5 and 6 and Comparative Examples 1 and 5, the uneven surface was not provided on the resin-coated surface of the metal plate.

(surface treatment)
In Examples 1 and 2 and Comparative Examples 2 and 4, CZ-8101 manufactured by MEC Co., Ltd. was used to treat the resin-coated surface or uneven surface so that the surface roughness Ra shown in Table 1 was obtained. A roughening treatment (etching) was performed at 30°C.

In Examples 3 to 6 and Comparative Example 5, nickel roughening plating was applied to the resin-coated surface of the metal plate. Plating bath composition: Ni metal content 130 g/L, boric acid 25 g/L, pH 3.3. Here, the Ni metal component was composed of nickel sulfamate tetrahydrate and Ni chloride as Ni salts. More specifically, nickel sulfamate tetrahydrate: Ni(NH ₂ SO ₃ ) _2.4H ₂ O=294 g/L (about 300 g/L), Ni amount 53.5 g/L, nickel chloride hexahydrate Hydrate: NiCl ₂ .6H ₂ O=approximately 310 g/L, Ni content was 76.5 g/L. The plating solution temperature was 60° C., and the current density was 10 A/dm ² . The treatment time was adjusted so that the surface roughness Ra in Table 1 was achieved.

In Comparative Examples 1 and 3, no surface treatment was applied to the resin-coated surface of the metal plate.

The surface roughness Ra shown in Table 1 was measured with a non-contact surface texture measuring device (PF-60) manufactured by Mitaka Kohki Co., Ltd. In the case of a roughened uneven surface with an uneven surface, a rectangular convex portion or a line The position of the top surface of the convex portion was observed. The observation magnification was 1000 times, the spot diameter was φ1.0 μm, the resolution was 0.1 μm on the X axis, 0.1 μm on the Y axis, and 0.01 μm on the Z1 axis (Z axis for measurement). The measurement settings are as follows.
Measurement pitch: 1 μm
Measurement range: 8.0 mm (scanning in a straight line) (In the case of measurement of the convex part of the uneven surface, the part is extracted later)
Measurement accuracy: X-axis 2 μm, Y-axis 2 μm, Z1-axis 0.3 μm
Measurement method: Scan Scanning speed: 100 μm/s
AF gain: Standard
Objective lens: SL100x (100x)

(injection molding)
A liquid crystal polymer (M-350B manufactured by ENEOS Liquid Crystal Co., Ltd.) was used as the resin material, and the resin member was fixed to the metal plate by insert molding using an injection mold. In all examples and comparative examples, the injection pressure was 150 MPa, and except for comparative example 5, the sprue bushing temperature was 360°C. In Comparative Example 5, the sprue bushing temperature was set to 170°C.

In Examples 1 to 6 and Comparative Examples 1 and 3, two gates were provided in the circumferential direction in the cavity of the injection molding die, so that two weld lines in the circumferential direction of the resin member were not present in the metal plate. was formed in places. In Comparative Examples 2, 4 and 5, four gates were provided, and thus four weld lines were formed in the resin member in the circumferential direction. In Example 2, the resin member was provided with two protrusions as shown in FIG. 11 at positions where weld lines are formed.

(Red check test)
A red check test was performed on the metal-resin composite to verify whether or not the red test liquid permeated between the resin member and the metal plate. Specifically, a small amount of the test solution was applied to the inner edge portion inside the resin member around the through-hole of the metal plate of the metal-resin composite with the tip of a wire, and left for 0.5 hours. If the test liquid does not leak outside the resin member after standing, the test liquid has not permeated the resin member, and it can be evaluated that the sealing property is good.

The test was conducted on an unheated metal-resin composite and a metal-resin composite after heating at 260°C for 2 hours. Regarding the unheated metal-resin composites and the heated metal-resin composites, in Examples 1 to 6 and Comparative Examples 2 and 4, five pieces each were subjected to the test. In Comparative Examples 1, 3 and 5, tests were performed on one unheated metal-resin composite. Table 1 shows the ratio (n/5 or n/1) of the number (n) of the total number (5 or 1) subjected to the test that did not leak the test liquid.

(Resin peeling test)
Using a block jig, a force was applied to the resin member of the metal-resin composite from the outside to the inside in the direction horizontal to the metal plate, and the resin member was peeled off from the metal plate. After that, residual resin adhering to the metal plate was confirmed. The fact that the resin remains on the metal plate means that the form of peeling is not peeling off from the interface between the metal plate and the resin member, but is caused by cohesive failure inside the resin member. It can be judged that the adhesion between the plate and the resin member is good. The punch block of the block jig had dimensions of width 8.3 mm×thickness 1.8 mm×length 26.0 mm. This resin peeling test was also performed on each of the unheated metal-resin composite and the metal-resin composite after heating (260° C., 2 hours).

The results are shown in Table 1. Here, "x" indicates that the residual resin is less than 10% of the area of the resin-coated surface, the residual resin is 10% or more and less than 50% of the area of the resin-coated surface, or the residual resin is interrupted. A case where the inside and the outside are connected is indicated by "Δ", and a case where the resin residue is 50% or more of the area of the resin-coated surface and the inside and the outside are blocked by the remaining resin is indicated by "○".

(Heat cycle test)
For each of the metal-resin composites of Examples 1 to 6, as shown in FIG. 12,

lids

81a and 81b were adhered to both sides of the resin member 73 of the metal-resin composite 71 with an adhesive 82 to simulate a semiconductor device. A test piece 91 was produced. However, this specimen 91 does not have a semiconductor chip in its internal cavity. The resin member 73 and the

lids

81a and 81b are made of a liquid crystal polymer (M-350B manufactured by ENEOS Liquid Crystal Co., Ltd.).

After subjecting the specimen 91 to a heat cycle test in which the temperature was repeatedly raised and lowered from -65°C to 160°C, the specimen 91 was submerged in water to check for air leakage. Table 1 shows the results. Table 1 shows the ratio of the number of specimens 91 with no air leakage to the total number of specimens 91 subjected to the test for each of the cases where the heat cycle test was performed 100 times, 200 times, and 500 times. is shown.

(Evaluation of tightness)
From the results of the above-mentioned red check test, resin peel test and heat cycle test, the sealing property of the internal space of the metal-resin composite was evaluated. Table 1 shows the results. In Table 1, "○" indicates that the airtightness is good, "△" indicates that it has a certain degree of airtightness, and "×" indicates that the airtightness is insufficient. indicates

(Discussion)
As shown in Table 1, in Examples 1 to 6, the number of weld lines in the resin member is set to two or less, and a roughened uneven surface or a roughened plating layer is provided on the resin-coated surface. It can be seen that the airtightness of the internal space was high in comparison. In addition to Examples 1 to 4 where the rectangular uneven surface was subjected to etching or roughening plating to form a roughened uneven surface, Examples 1 to 4 in which roughening plating was performed without forming an uneven surface on the resin-coated surface and 6 also ensured high airtightness of the internal space.

On the other hand, in Comparative Example 1, since neither the uneven surface nor the roughened plating layer was provided on the resin-coated surface, the sealing performance was low. From Comparative Example 3, it can be seen that even if the resin-coated surface is provided with a rectangular concave-convex surface, sufficient sealing performance cannot be ensured unless roughening treatment is performed. Moreover, from Comparative Examples 2, 4, and 5, it can be seen that as the number of weld lines formed in the resin member increases, the hermeticity deteriorates.

From the above, it was found that according to the metal-resin composite described above, the sealing of the internal space by the resin member can be improved.

(resin adhesion)
For each of the nickel-plated copper metal plate and the untreated copper metal plate, after fixing the resin member, the resin member was peeled off and the shear strength was measured. Table 2 shows the results.

From Table 2, it can be seen that the untreated metal plate has a higher shear strength, although the surface roughness Rz of the resin-coated surface is about the same. This surface roughness Rz means the maximum height conforming to JIS B0601:2001. It is also known that nickel plating generally has low resin adhesion. The surface roughness Rz was measured with a laser microscope (VK-X150) manufactured by Keyence Corporation at a magnification of 1000 and a spot diameter of φ0.8 mm. The objective lens was 100 times. The measurement range (measurement area) was set to 105.737 μm×141.029 μm, which is the size of the image captured after the measurement with the laser microscope. Analysis was performed by drawing a horizontal line (vertical line) in the line roughness measurement.

For this reason, even when a nickel roughening plating layer with low resin adhesion is provided on the resin-coated surface, the internal space can be sufficiently sealed as shown in Table 1. It can be said that high sealing performance is exhibited even when a roughening plating layer other than nickel is provided.

Reference Signs List 1, 71 metal-

resin composite

2, 72 metal plate 2a

inner edge

3, 73 resin member 4 through

hole

5, 15

uneven surface

5a, 15a

rectangular recess

5b, 15b rectangular protrusion 5c top surface 6 roughened plating layer 7 weld line 8a to 8c Notch 9 Projection 51 Semiconductor chip 52

Bonding wire

81a, 81b Lid 82 Adhesive 91 Specimen La Length of long side of rectangular concave portion and rectangular convex portion Lb Short side length of rectangular concave portion and rectangular convex portion Length Pa Pitch in the long side direction of the rectangular recess Pb Pitch in the short side direction of the rectangular recess R1 First recess group R2 Second recess group Sb Back surface Sf Front surface

Claims

A metal-resin composite comprising a metal plate and a resin member fixed to the metal plate, wherein an internal space is defined by a sealing member including the resin member,
The resin member has a frame shape extending on the metal plate so as to surround the inner space, and one or two weld lines are present in the circumferential direction of the frame-shaped resin member,
The resin-coated surface of the metal plate covered with the resin member is roughened by rectangular concave portions and rectangular convex portions that are alternately arranged in one direction and each direction perpendicular to the resin-coated surface in a plan view of the resin-coated surface. A metal-resin composite having an uneven surface.
The metal-resin composite according to claim 1, wherein the roughened uneven surface has a surface roughness Ra of 0.2 µm or more.
The metal-resin composite according to claim 1 or 2, wherein each of the rectangular concave portion and the rectangular convex portion has a rectangular shape in a plan view of the resin-coated surface.
The metal-resin composite according to any one of claims 1 to 3, wherein the rectangular projection has a convex curved surface on the resin member side.
A metal-resin composite comprising a metal plate and a resin member fixed to the metal plate, wherein an internal space is defined by a sealing member including the resin member,
The resin member has a frame shape extending on the metal plate so as to surround the inner space, and one or two weld lines are present in the circumferential direction of the frame-shaped resin member,
A metal-resin composite including a roughened plating layer on the resin-coated surface of the metal plate covered with the resin member.
The metal-resin composite according to claim 5, wherein the roughened plating layer contains nickel.
The frame-shaped resin member is provided by sandwiching the metal plate from both sides in the plate thickness direction at a part in the circumferential direction,
The metal-resin composite according to any one of claims 1 to 6, wherein the weld line is formed in the circumferential direction of the frame-shaped resin member at a location where the metal plate does not exist inside the resin member. .
The metal-resin composite according to any one of claims 1 to 7, wherein a cut mark is present at a location where the weld line of the resin member is formed.